Machine for coating metal on metal pipes or tubing



Jan. 30, 1951 R. A. OTTO 2,540,005

MACHINE FOR COATING METAL ON METAL PIPES OR TUBING 4 Sheets-She?v 1 Filed May 5, 1948 HAT A TTOR/VE' Y6 Jan. 30, 1951 R. A. OTTO r MACHINE FOR ZNVENTOR. RA y/va/w ,4, 0 7m,

A TTORIVE Ye? 4 Sheets-Sheet 2 COATING METAL ON METAL PIPES OR TUBING Filed May 5, 1948 Jan. 30, 1951' R.'A. OTTO MACHINE FOR COATING METAL ON METAL PIPES 0R TUBING 4 Sheets-Sheet 5 Filed May 5, 1948 Ema-m1 U INVENTOR. AM /va/a/a ,4. 07m,

A 770R NE vs Jan. 30, 1951 R. A. OTTO MACHINE FOR COATING METAL on METAL PIPES OR TUBING 4 Sheets-Sheet 4 Filed May 5, 1948 INVEN TOR. R4 WWW/V0 ,4 OTTQ AH IH Patented Jan. 30, 1951' UNITED STATES r MACHINE FOR COATING METAL N METAL PIPES 0R TUBING Raymond A. Otto, Gwynhurst, DeL, asslgnor of one-half to Horace J. Heffelfinger, Claymont,

Del.

' Application May 5, 1948, Serial No. 25,217

11 Claims. (01. 91-122) The invention relates to a machine for coating with lead any pipe or tubing such as copper,

- machine for this purpose which will homogene ously bond a covering of lead of any desired thickness to the external surface of such pipes or tubing.

Another object of the invention is to provide a machine which will also coat hollow or solid stock of round, square, diagonal or any other shaped surface with a homogeneously bonded lead covering.

A further object of the invention is to provide a machine adapted to apply a homogeneously bonded coating of lead to pipes, rods and similar stock, and equipped with a storage tank or reservoir capable of feeding by gravity chemically pure or antimony lead to a vessel or receptacle through which the stock is passed horizontally, but the vessel or receptacle may be positioned for passage of stock through it in a vertical position or in an inclined position at any angle or degree between vertical and horizontal positions.

It is also an object of the invention to provide a machine in which the molten contents of the vessel or receptacle through which the stock is passed are maintained under a predetermined pressure adapted to maintain molten lead as it is exuded in constant contact with partially cooled or partially solidified lead covering so that the lead covering at the point of transition from a molten to a solid condition will not be pulled away from the exuded molten lead surrounding the stock and cause any break in the continuity of the lead covering. I

Another object of the invention is to enable the pressure within the receptacle or vessel to be exerted against the partially solidified lead covering which functions in the nature Of a piston so that the pressure within the vessel or receptacle may be employed for forcing the coated stock out of the machine, thereby obviating the necessity of pulling or pushing the stock out of the machine after the coating is applied to the stock.

It is also an object of the invention to provide guiding means located at the ends of the tank or vessel adapted to be readily removed and replaced by similar guiding means for adapting the machine for coating stock of different diameters.

Another object of the invention is to equip the tank or vessel through which the stock to be coated is passed with pressur responsive means for controlling the operation of a motor operated 2 pump or compressor so as to maintain within the tank or vessel a predetermined pressure to insure continuity of the lead coating applied to th stock and also the automatic discharge of the coated stock from the machine.

Another object of the. invention is to provide at the outlet end of the tank or vessel guiding v means having spaced guiding fingers arranged to receive the end of the stock and accurately guide the same and providing intervening spaces for permittin the molten metal to fiow around them and fill the grooves temporarily formed in the coating by the guiding fingers so that a full and complete coating of the lead will be carried by the stock through a shaping or finishing die.

Another object of the invention is to provide at a point intermediate the ends of the shaping or guiding die means for reducing the temperature of the lead coating for causing a solidification of the same prior to the coated pipe leaving the shaping or finishing die and thereby enable the pressure within the vessel or receptacle to automatically force the coated stock out of the machine.

With the abov and other objects in view, the

invention consists in the construction and novel combination and arrangement of parts hereinafter fully described, illustrated in the accompanying drawings and pointed out in the claims hereto appended, it being understood that various changes in the form, proportions, and minor details of construction, within the scope of the claims, may be resorted to without departin from the spirit or sacrificing any of the advantages of the invention.

In the drawings:

Figure 1 is an elevation, partly in section and partly diagrammatic, of one form of a machine constructed in accordance with this invention for applying a metallic coating to stock;

Figure 2 is an enlarged vertical longitudinal sectional view of the tank or vessel and the shapin or finishing die, a pipe or tube being shown in position for coating;

Figure 3 is a similar view illustrating the arrangement of the pipe or tubing as it is leaving the shaping or finishing die and showing the ends of the tank or vessel closed by valves;

Figure 4 is a transverse sectional view taken substantially on the line 44 of Figure 2;

Figure 5 is a transverse sectional view taken substantially on the line 5-5 of Figure 2;

Figure 6 is a transverse sectional view taken substantially on the line 6-6 of Figure 3;

Figure 10 is a detail longitudinal sectional view of a piece of tin coated copper tubing having a lead covering;

Figure 11 is an elevation partly in section and I partly diagrammatic Of a machine illustrating another form of the invention for increasing the pressure of the molten metal within the machine and the pressure of the aeriform fluid to which the molten metal is subjected to effect automatic discharge of the coated stock from the machine.

Referring particularly to Figures 1 to 9 in the accompanying drawings, in which is illustrated one form of the invention, I designates a vertical storage tank orreservoir, preferably of cylindrical form, arranged in a vertical position and having its walls provided with a coating 2 of heat insulating material such as refractory fire brick, asbestos or the like, and provided with a removable cover 3. The supply tank I, which is designed to contain molten lead or other molten metal, is mounted on a suitable supporting frame 4 and is connected at its bottom with a sealed coating receptacle or vessel 5 located below the tank or reservoir and adapted to receive by gravity feed molten metal '5 from the tank or reservoir. The bottom 1 of the supply tank I is provided with an opening 8 which is covered by a screen 9 and if there should be any impurities in the lead they will be forcedto the surface of the molten metal so that only chemically pure or antimony lead or other metal will be supplied to the receptacle or vessel 5. The tank or reservoir is connected with the receptacle or vessel 5 by a vertical pipe or conduit It! provided at its upper end with a flange ll bolted or otherwise secured to the bottom of the supply tank I. The lower end of the pipe or conduit l which communicates with the interior of the tank or vessel i is secured to the same by a flanged nip le I 2 bolted or otherwise secured to the receptacle 5, as clearly illustrated in Figures 2 and 3 of the drawings.

The molten lead within the storage tank or reservoir is maintained at a proper temperature by a circular gas burner [3 located directly below the bottom I of the tank or reservoir l and provided with jets l4 directed towards the bottom I. Lead melts at 618.8" F. and the temperature should be sufiiciently above the melting point of lead to maintain the molten condition thereof. The melting point of tin is 466 F. and when applying a coating of tin to the stock the temperature is maintained sufficiently above the melting point of the tin to maintain it in a molten condition. The flow of gas to the burner is controlled by a suitable valve and in practice automatic means will be employed for maintaining the contents of the storage tank or reservoir at the required temperature.

The pipe I 0 for conducting the molten metal from the storage tank to the receptacle 5 is provided with a valve I 6 for controlling the flow of molten metal to the receptacle 5 and also for shutting off the flow when desired or required.

The receptacle or vessel 5 is also preferably of cylindrical form and is disposed horizontally and is provided at its top, ends and sides with a heat insulating covering ll of refractory fire brick, asbestos or the like, and the bottom is exposed to the flames from jets III of a gas burner l8, disposed below the receptacle! and supported in suitable brackets 20. The gas burner, which is provided with a valve 2| for controlling the flow of the gas, maintains the molten metal within the receptacle 5 at the desired temperature and in practice suitable automatic means will be provided for maintaining the contents of .the receptacle at the required temperature.

The receptacle or vessel 5, which is provided at one end with a suitable drain valve 22, has openings 23 and 24 in its front and rear ends through which the stock is passed for coating it with molten lead contained within the receptacle. The front end of the tank at the opening 23 is provided with a stufllng box 25 of any suitable construction detachably secured by bolts 25 to the front wall of the tank to enable it to be removed and replaced by a similar stufling box having an opening. of a diii'erent diameter so that tubular and solid stock of different diameters may be coated with the molten metal combined within said receptacle or vessel 5. The stufling box 25 is provided at its inner end with an attaching plate 21 through which pass the bolts 26 and within the stufling box is arranged packing 28 which is maintained in tight contact with the stock passing through the receptacle 5 by means of an adjustable gland 29 having an annular flange 30 secured by bolts 3| to a projecting annular flange 32 provided at the outer end of the stufilng box. The opening 23 in the front end of the receptacle! is of sufficient size to permit stock of the desired range of diameters to pass through it so that it is only necessary to provide a stufilng box of the required diameter to fit the pipe or red to be coated.

The opening 24 at the rear or outlet end of the receptacle or vessel 5 is adapted to receive a skeleton stock guide 33 consisting preferably of a circular plate provided with a central opening 34 of a diameter greater than the interior diameter of the stufflng box at the front end of the receptacle 5 and provided with a horizontally disposed circumferentially spaced guide fingers 35 preferably circular in cross section and having the innermost portions of their eripheries spaced to correspond to the interior diameter of the stuffing box. In Figure 8 of the drawings, four horizontally disposed guide fingers are illustrated and are arranged diametrically opposite each other and the members of each pair of diametrically disposed fingers are spaced apart a distance corresponding to the exterior diameter of the stock being coated so that they will form an accurate guide for the inserted end of the stock for directing the stock into a shaping or finishing die 36. The front ends 31 of the fingers 35 are beveled to form a flaring entrance for guiding the stock into the space circumscribed by the fingers and the spacing of the fingers from one another provides passages for permitting the molten metal to flow past the fingers and into the shaping, or finishing die for filling the grooves formed by the fingers in the metal coating so that when the covered or coated portions of the stock pass the fingers thecoating will completely flll this space between the stock and the shaping or finishing die which is adapted to finish the lead coating and smooth it off to a bright polished surface.

The shaping or finishing die which is disposed horizontally extends from the rear or outlet end of the tanker vessel 5 and is provided adjacent the same with an annular flange 38 secured by screws 33 to the rear end wall 40 around the the flange 38 and the end wall 40 and is pierced by the screw 39. By removing the screws 39 the shaping or finishing die and the guide 33 may be removed from the end wall 40 and a guide and a shaping or finishing die of a different diameter may be substituted for the ones removed from the end wall to provide for coating a pipe or rod of a different size. The shaping or finishing die has a long cylindrical interior coating shaping surface of uniform diameter and is interiorly tapered at its rear end to form an outwardly flared outlet 4| from which the coated stock is discharged.

The tubular ors'olid stock is introduced into the machine by inserting it in the stufilng bo is opened by the front end of the stock which is moved horizontally through the molten metal 6 within the receptacle and its front end is introduced within the space within the guide fingers, being guided and centered by the tapered front ends 31 of said fingers. As soon as the front end of the stock reaches the rear end of the receptacle 4, a manually operable slide valve 45 is raised to permit the pipe to be introduced into the guide 33. The flap valve 44 is hinged at the bottom at 46 and is adapted to close automatically as soon as the rear end of the stock leaves the front end of the receptacle 5. While said die. The tank or vessel 5 is provided at the top with a pressure relief valve 58' of any desired construction which is adapted to relieve the receptacle or vessel of any excess pressure beyond a predetermined amount. The pump or mpressor is connected by a suitable stand pipe 0 5 '|s\with the interior of the receptacle 5 and it has i lower end suitably secured within a flanged nipple 58 located at the top of the tank and bolted or otherwise secured to th same. The pump or compressor is shown located above the receptacle 5 but it may, of course, be arranged at any other convenient location. The heat of the molten metal within the receptacle or vessel maintains the stock at the same temperature as the molten metal so that a homogeneous bond between the stock and the coating is assured. when the stock has been previously tinned, as a homogeneous lead coating cannot be applied to any stock unless it is thoroughly tinned beforehand. The vessel or receptacle is entirely filled with molten lead or other metal and the stand pipe 51 is provided at its upper end with a petcock 5'l which, when open, will enable the {operator to readily see when the stand pipe 51 isl'fllled to its upper end. The application of aeriform fluid pressure to the metal within thestand pipe 51 will enable suflicient pressure to be applied to the molten metal within the receptacle or vessel to insure an automatic discharge of the coated stock from the machine as the said pr essure and the pressure produced by the metal within the the specific gravity of the molten metal within the receptacle or vessel will float the valve 44 to its closed position and maintain it closed the flap valve 44 may be spring loaded by a leaf spring 42 secured at one end to the front end wall of the receptacle or vessel and having its other end 7 free and bearing against the flap valve 44. The leaf spring will automatically close the flap valve when it is free to move, whether th receptacle or vessel contains molten metal or is empty. The slide valve 45 is operated by a rod or stem 41 extending through an opening in the top wall of the receptacle or vessel and through a bushing 48 in the insulation I1 and provided at its upper end with a suitable handle adapted to be readily grasped by the operator for raising and lowering the valve to open and close the same.

The shaping or finishing die is surrounded at a portion intermediate of its ends by a water jacket 49 to the top and bottom of which are connected inlet and outlet pipes 50 and 5| provided withvalves 52 and 53 for controlling the flow of water through the water jacket. The water jacket cools the molten lead sufilciently to solidify the same and cause the coating to leave the shaping or finishing die 30 in a solid condition. In order to prevent the solidified or partially solidified portion of the lead coating from pulling away or separating from the molten metal at or about the point where the molten metal coating is changed from the molten condition to a solid or semi-solid condition, an air or other aeriform fluid pressure is maintained in the upper portion of the receptacle or vessel 5 by means of a pump or compressor 54 operated by an electric motor 55 or other suitable means. The weight of the molten metal within the vessel or receptacle and the aeriform pressure applied thereto will maintain the molten metal within the shaping or finishing die in contact with the solidified or partially solidified coating so that there will be no interruption or breaking of the continuity of the coating of the stock as it leaves vessel or receptacle acting on the solidified portion of the coating will force the coated stock out of the shaping or finishing die.

The surface to be coated is cleaned by grinding, abrasion, pickling or the like and, as illustrated in Figure 10 of the drawings, in coating copper tubing 59 the copper'tubing may have a thin tin coating or plating B0 to which the lead coating BI is applied, but the coating or plating of tin may, of course, be omitted and the lead coating may be applied directly to the exterior surface of the stock, but for coating stock with a homogeneous bonded lead coating the tining of the stock beforehand is necessary. In coating tubular stock the ends of the tubing are plugged to prevent access ofthe molten metal to the interior of the tubing.

The electric motor is connected by wires 62 and 63 with a magnetic starter 64 of conventional construction which is supplied with power from line wires 65 and 66 by wires 61 and 68 which are adapted to be interrupted by a main knife switch 69 which is adapted to be opened and closed to shut off the power from the magnetic starter and to feed power to the same. The magnetic starter is manually controlled by a push button switch 10 and is automatically controlled by a pressure responsive device ll The push. button switch is connected by wires 12 and 13 with the magnetic starter and the pressure responsive device is connected with said magnetic starter by wires 14 and 15. The pressure responsive device is of conventional construction and is connected by a pipe 16 with the interior of the receptacle or ves sel 5 so that when the pressure within said receptacle reaches a predetermined degree, the motor will be automatically cut off and when it falls blow a, predetermined pressure, the motor will be operated to build up the pressure.

The machine is operated by closing the knife switch 69 and pressing the push button 10 and when the pressure builds up to the required amount, the motor will be automatically stopped and the operation of coating the stock may be begun by introducing the stock into the tank or vessel 8, as before explained. At the completion of the work the motor may be manually stopped by pressing the push button 10 and current may be cut oil entirely from the machine by opening the knife switch. 1

While gas burners are illustrated in the drawings for maintaining the molten metal in the supply tank and in the sealed coating receptacle in a molten condition, electrical or any other suitable heating means may be employed for maintaining the molten condition of the metal, and metals other than lead and alloys of metals may be employed for coating hollow or solid stock. 1

Referring particularly to Figure 11 of the drawings, I'I designated a vertical supply tank or reservoir, of the same construction as that heretofore described, connected by a vertical pipe or conduit I8 with a sealed coating receptacle or vessel 18 of cylindrical form arranged horizontally and designed to be constructed substantially the same as that heretofore described with the exception that the valve 44 for closing the opening 80 in the front wall 8| of the vessel or receptacle is dispensed with anda length of pilot stock 82 primarily forms a closure for the opening 80 in the front wall of the vessel 'or receptacle.

The front wall of the vessel or receptacle has detachably mounted on it a plate 88 having a central opening from which extends an annular flange 84 into which the pilot stock is introduced for closing the entrance opening at the front of the vessel or receptacle. A length of stock 88 is attached to the pilot stock 82 and successive lengths of stock are connected by welding or other suitable means with one another to enable,

the stock to be coated to be continuously introduced into the vessel or receptacle at the front thereof and at the same time maintain theopening in the front wall of the vessel or receptacle closed. The rear end of the last piece of stock of the string will be plugged and when the said rear end has, by forward movement, reached the opening 80, the flow of metal through the pipe 18 may be cut oil" by a valve 88 and the molten metal will be relieved of the aeriform fluid pressure hereinafter described and then drained from the vessel or receptacle by means of a drain valve 8! to prevent the loss or leakage of molten metal from the front opening when the last piece of stock is withdrawn therefrom. However, the removable plate 88 may be equipped with a gate valve or other suitable closure for closing the front opening. This will obviate the necessity of draining the molten metal from the vessel or receptacle. Also instead of using an exteriorly arranged gate valve an interiorly arranged flap valve 44 may be employed.

The detachable plate 88 is removable for enabling plates having annular flanges of different diameters to be provided for accommodating stock' of diilerent diameters and in practice the opening 88 will be of suiiicient size to permit the passage of stock of the various diameters for which the machine is designed for coating. The tank or reservoir and the receptacle or vessel are provided with insulation 88 and 88 and the metal within the tank or reservoir and the receptacle or vessel is maintained in the molten condition by burners 88 and 8|, constructed as before described.

The left hand end of the vessel or receptacle is shown broken away for convenience of illustraupper piston head 86 of a piston rod 81 extending through the lower end of the cylinder 85 and into the upper end of a lower cylinder 88 and provided at its lower end with a piston head 88 of less diameter than the upper piston head 88. The lower vertical cylinder 88 extends upwardly from, and has its lower end communicating with. the vessel or receptacle 18 and constituting a stand pipe and designed to be filled with molten metal and provided at its upper end with a petcock I88. which when open will indicate to the operator when the molten metal has risen in the lower cylinder or stand pipe up to the petcock I88, which is then closed. The pipes 88 and '84 extending from the air compressor to the top and bottom of the upper main cylinder are provided with manually operable valves l8l and I8! and the air pipe 88 is also provided with a pressure relief valve for automatically controlling the pressure within the main cylinder and above the piston head 88 so that a constant predetermined pressure may be maintained against the upper I piston head 88 when the air compressor is in operation and in communication with the upper portion of the cylinder 88. The pipe 84 enables pressure to .be applied to the lower face of the piston head 88 for elevating the same. The manually operated valve I02 of the air pipe 84 is normally closed and the manually operable valve llil is open when the machine is in operation. Any suitable venting means may be provided for enabling air from the upper portion of the cylinder to be vented when compressed air is introduced into the lower end of the upper cylinder for elevating the piston and the man-'- ually operated valve IOI of the pipe 88 is closed.

Approximately two-thirds of a cubic foot of lead will coat feet of stock of 1 inch diameter with a lead coating 4 inch thick. The lower stand pipe or cylinder 88 is designed to have a capacity sufficient to coat 100 feet of 1% inch stock with a lead coating A, inch thick, and the amount of lead used from the tank or reservoir 11 will indicate the amount of lead in the lower cylinder or stand pipe 88 so that the operator, by maintaining a predetermined amount of lead in the tank or reservoir 11 will know that the lower cylinder or stand pipe 88 will be filled with molten metal. The weight of the molten metal within the vessel or receptacle and the stand pipe or lower cylinder 88, supplemented by the aeriform pressure produced by the air compressor, will be ample to automatically discharge the coated pipe from themachine. The'area of the lower piston head 88 is less than the area of the upper piston head 86 and the pressure may 9 ing die having. a long cylindrical interior coating shaping surface of uniform diameter being interiorly tapered at its outer end to provide a outwardly flared exit portion for the coated stock, and means for applying downward pressure on thamolten metal within the receptacle and outward pressure at the rear opening of the receptacle for forcing the coated stock out of the die.

a A machine for coating hollow and solid stock witlfmetal including a molten metal receptacle having openings in its front and rear walls arranged to permit the stock to be moved through the receptacle to recelveg metal coating, a shap ing and finishing die of bular form extending from the rear opening in position to receive the coated stock, means for solidifying the molten metal of the coatingwhile the stock is being moved through said die, and means for applying walls arranged to permit the stock to be moved longitudinally through-the receptacle to receive a metal coating, a shaping and finishing die of tubular form extending from the rear opening in position to receive the coated stock, means for solidifying the molten metal of the coating while the stock is being moved through said die, and means for subjecting the molten metal within the receptacle-to pressure to maintain the molten metal within said die in constant contact with the solidified portion of the coating to prevent such solidified coating from pulling away from the molten metal and interrupting the continuity of the coating, and for forcing the coated stock out of said die.

4. A machine for coating hollow and solid stock with metal including a molten metal receptacle having front and rear openings in its walls arranged to permit the stock to be moved through the receptacle for coating the stock with molten metal, a shaping and finishing die extending from the rear opening in the. receptacle, and

guiding means located at the rear opening and having spaced portions arranged ,to engage directly the stock and forming passages for the flow of metal through the guiding means and around the stock and into said die.

5. A machine for coating hollow and solid stock with metal including a molten metal'receptacle having front and rear openings in its walls arranged to permit the stock to be moved through the receptacle for coating the stock with molten metal, a shaping and finishing die extending from the. rear opening in the receptacle, and guiding means located at the rear opening in the receptacle and having spaced longitudinally disposed guiding fingers arranged to engage the stock and center the same with respect to the die and forming passages for theflow of molten metal through the guiding means around the stock and into said die, said fingers being circular in cross section and having beveled front ends forming a flaring entrance to the guiding means. I

6. A machine for'coating hollow and solid stock with metal including a sealed molten metal receptacle having openings to permit stock to be moved through the receptacle, a shaping and 10 finishing die extending from one of 'the openlugs and arranged "to receive coated stock and provided with means for solidifying the molten metal coating, and a pump connected with the said receptacle, a motor for actuating the pump for'subjecting the molten metal to pressure for maintaining molten. metal within the shaping and finishing die in contact with a solidified partion of thecoating and for automatically forcing the coated stock out of the die, and a pressure responsive device communicating with the receptacle for controlling the operation of the motor for maintaining a predetermined pressure within the receptacle.

7. A machine for coating hollow and solid stock with metal including a sealed molten metal receptacle having openings and a supply tank connected with the receptacle and arranged to providea gravity feed of molten metalto said receptacle, a shaping and finishing die extending from one of the openings and arranged to receive coated stock and provided with means for solidifying the molten metal coating, and a pump connected with the said receptacle, a motor for actuating the pump for subjecting the molten metal to pressure for maintaining molten metal within the shaping and finishing die in contact with a solidified portion ofthe coating and for automatically forcing the coated stock out of the die, and a pressure responsive device communicating with the receptacle for controlling the operation of the motor for maintaining a predetermined pressure within the receptacle.

8. A machinefor coating hollow and solid stock with metal including a sealed molten metal receptacle having openings to permit stock to be moved through the receptacle, a shaping and finishing die extending from one of the openings and finishing die in contact with a solidified portion of the coating and for automatically forcing the coated stock out of the die, a pressure responsive device communicating with the receptacle for controlling the operation of the motor for maintaining a predetermined pressure within the receptacle, and a manually operable circuit closing device for controlling the operation of the motor.

9. A machine for coating hollow and solid stock with metal including a molten metal receptacle having openings in its walls through which stock is passed to receive a metalcoating, a cylinder connected with the receptacle, a piston operating in the cylinder, means for feeding molten metal to the receptacle and for introducing the same into said cylinder, and means for actuating the piston for subjecting the molten metal to pressure for maintaining the molten metal in the receptacle in contact with a solidified portion of coated stock for automatically forcing the coated stock out of the machine.

10. A machine for coating hollow and solid stock with metal including a molten metal receptacle having openings in its walls through which stock is passed to receive a metal coating, a pair of cylinders of different diameters, the smaller cylinder being connected with the receptacle, a piston having piston heads operating within said cylinders, means for introducing molten metal into the receptacle and into the 11 smaller cylinder, and means for introducing fluid pressure into the larger cylinder for actuating the piston to subject the molten metal to pressure for maintaining the molten metal in the receptacle in contact with a solidified portion of coated stock for automatically forcing the coated stock out 01 the machine.

11. A machine for coating hollow and solid stock with metal including a molten metal receptacle having openings in its walls through which stock is passed to receive a metal coating, a pair of cylinders of different diameters, the smaller cylinder being connected with the receptacle, a piston having piston heads operating within said cylinders, and means for introducing fluid pressure into the larger cylinder at either side of the piston head within the same for actuating the piston to subject the molten metal to pressure and for retracting the piston, the pressure on the molten metal within the receptacle maintaining said molten metal in contact 12 with a solidified portion 01' coated stock for automatically forcing the 'coated stock out of the machine.

RAYMOND A. o'rro.

REFERENCES CITED The following references are of record in the file of this patent:

. UNITED STATES PATENTS Number Name Date 2,092,284 McCarroll et al Sept. 7, 1937 2,214,108 Nichols Sept. 10, 1940 2,386,090 Bouget Oct. 2, 1945 2,432,854 Bassett et a1 Dec. 16, 1947 2,482,021 Mickelson Sept. 13, 1949 FOREIGN PATENTS Number Country Date 845,943 France Sept. 5, 1939 

